The present invention relates to a semiconductor memory device which sequentially reads out data from a plurality of banks. More specifically, the invention relates to a serial-access ROM which incorporates an address counter for sequentially generating addresses, and which starts sequentially outputting data in synchronism with serial-access clocks when a read start address is set in the address counter.
In general, the access time of a ROM is long. In the case of a serial-access ROM, the serial cycle time is shortened by grouping the memory cell arrays into a plurality of banks and providing sense amplifiers for the respective banks. Data read out from the banks are sensed and amplified at a time, and the resultant data are sequentially output from a single output buffer.
A conventional serial-access type semiconductor memory device, which sequentially reads out data from a plurality of banks, has a problem when an upper-address bank is designated by a read start address. To be specific, a busy period when serial access is impossible is produced between a first-cycle data read operation and a second-cycle data read operation, and the access cycle time is lengthened thereby.